Ex-Formula One star John Watson says the new Hollywood movie Rush has taken him back 37 years to the day he helped save the life of three-time world champion Niki Lauda.

Belfast-born Watson, now 67, was one of the first on the scene of the horrific crash and subsequent fireball that engulfed the Austrian's Ferrari during the 1976 German Grand Prix at the Nurburgring.

The accident is dramatically recreated in the Ron Howard-directed film, which recounts the fierce rivalry between Lauda and English driver James Hunt.

Lauda suffered horrendous burns, losing most of his right ear, the skin on his head, his eyebrows and eyelids.

But Watson, a five-time Grand Prix winner, held his terrified friend's hand during the ordeal –and, in a bid to downplay the horror, told him there was nothing wrong with Lauda's ruined face.

"I arrived at the point when Niki was being hauled out of the car," said Watson who, along with the now 64-year-old Lauda, attended the movie's premiere in London's Leicester Square on Monday night. "I got down on my knees and he then lay down and put his head on my lap. I was trying to keep him as settled as possible as we waited for the ambulance

"He didn't know the full extent of his injuries and was lucid but obviously in shock.

"I could see that parts of his scalp were charred black and there were also severe burns to his forehead.

"At one point he asked me what his face looked like and I said: 'You're fine, you've nothing to worry about, you're OK'."

He added: "There was no point in me saying 'your scalp is charred back and there are lumps of it coming out', so I tried to assure him as much as I could until we got him into the ambulance."

When Lauda's then wife Marlene first saw him after the accident, she fainted.

Ironically, Lauda had earlier tried to get the race cancelled because he believed the Nurburgring was too dangerous, but was out-voted by the other drivers.

Astonishingly, the Austrian was back in the cockpit only six weeks later, and battled for the title with Hunt right up until the last day of the season.

"Motor racing in those days was hazardous," said Watson.

"Some of the accidents that occurred in the 1970s were gruesome; it was all part of that era. Roughly every year, out of 30 drivers, something like two a year were losing their lives. On reflection, those were pretty poor odds."

In the following race in Austria John, driving a Penske (he had driven a Lotus-Ford in Germany), won his first Grand Prix; Lauda, a close friend, went on to win two further world championships, first with Ferrari and then McLaren.

John said Lauda's decision to compete (at Monza in Italy) so soon after the Germany crash was one of the most courageous things he had ever seen anyone do.

"His head was covered in bandages. He wasn't a picture, that's for sure," he said.

"He had third degree burns and you could have pulled bits of his scalp out with your fingers if you'd wanted to.

"At Monza he was a different man to the one we'd seen at Nurburgring before the accident – in so many ways."

Rush tells of the fierce rivalry between drivers James Hunt (played by Chris Hemsworth) and Niki Lauda (Daniel Bruhl) during the 1976 F1 season. Flamboyant English playboy Hunt, who died from a heart attack at 45, won the world title by just one point from defending champion Lauda following a dramatic series during which the Austrian nearly died in a horrific accident at the Nurburgring in Germany. Miraculously Lauda, despite his disfiguring injuries, returned after only 41 days to challenge Hunt for the title, which went all the way to the final race. He would go on to win two more world championships.